The present disclosure relates to an optical fiber manufacturing apparatus and a start-up method of the same.
In an optical fiber manufacturing process, an optical fiber preform is heated and melted by a drawing furnace, so that a glass optical fiber is drawn therefrom. Then, a resin is applied onto an outer circumference of the glass optical fiber by a coating mechanism also called a die. Generally, this die has an insertion hole through which the glass optical fiber to be coated is inserted, and the die applies the resin onto an outer circumference of the glass optical fiber that passes through this insertion hole serially. The applied resin is cured by a curing mechanism arranged downstream from the die, and the glass optical fiber is thereby formed into an optical fiber (also called, a bare optical fiber) having a coating layer formed therearound.
The outer diameter of the glass optical fiber needs to be made smaller than the insertion hole of the die before this process of manufacturing the optical fiber, and thus when the manufacture of the optical fiber is started, the glass optical fiber is serially drawn out from the optical fiber preform such that the glass optical fiber is made thinner (see, for example, Japanese Laid-open Patent Publication No. H10-330133). Hereinafter, drawing out a glass optical fiber from an optical fiber preform for adjustment where the glass optical fiber is made thinner than the insertion hole of a die will be referred to as “pre-drawing”, and will be distinguished from “drawing” where the glass optical fiber (the glass optical fiber to be coated), which has been adjusted in outer diameter such that the glass optical fiber is able to be inserted in the insertion hole of the die, is drawn out from the optical fiber preform.